1. Field of the Invention
This invention relates to an apparatus for retaining cargo on a platform.
The apparatus described herein was designed for use on a container trailer of the type used to load baggage on an aircraft. Such a trailer is described in U.S. Pat. No. 4,049,286, issued to G. W. Francis, Jr. on Sep. 20, 1977. As mentioned in the Francis patent, because the containers have a relatively large height to width ratio, the baggage containers must be firmly latched in position to prevent both horizontal and vertical movement.
2. Discussion of the Prior Art
Of course the need for firmly latching a load in position is not limited to baggage trailers. Loads on trucks, and in tractor trailers and other vehicles are often locked in position to prevent shifting during travel. Examples of mechanisms for latching loads in position are disclosed in U.S. Pat. No. 3,399,921, issued to P. E. Frost et al on Sep. 3, 1068; U.S. Pat. No. 3,778,012, issued to R. J. Ferandez on Dec. 11, 1973; U.S. Pat. No. 3,810,534, issued to E. Prete, Jr. on May 14, 1974; U.S. Pat. No. 4,415,298, issued to W. Voight on Nov. 15, 1983; U.S. Pat. No. 4,696,609, issued to S. C. Cole on Sep. 29, 1987; U.S. Pat. No. 5,109,971, issued to F. Riner on May 5, 1992 and U.S. Pat. No. 5,575,599, issued to J. A. Conlee et al on Nov. 19, 1996.
For the most part, the patented devices, including the Francis assembly, are not fully automatic, are somewhat complicated or do not engage opposite sides of a load for latching the load in position. As mentioned above, it is important to engage a load at opposite sides to limit or prevent horizontal movement, and, in most cases, to also limit or prevent vertical movement of the load. While the Francis assembly is adapted to engage opposite sides of a container, the assembly is not automatic, i.e. it is necessary to operate a crank manually in order to effect latching. Thus, a need still exists for a fully automatic mechanism or apparatus for retaining cargo on a platform which is actuated by loading of the cargo onto the platform.
An object of the present invention is to meet the above defined need by providing a fully automatic apparatus for holding cargo in position on a platform which, when actuated by loading of the cargo onto the platform, engages opposite sides of the cargo.
In broadest terms, the invention is an apparatus for retaining cargo on a platform comprising:
(a) a pair of spaced apart retaining means in said platform for movement between a retracted position below a top of said platform and an extended position above said top surface of the platform;
(b) pivot arm means in said platform normally projecting above the top of the platform for downward movement when engaged by cargo placed on the platform; and
(c) linkage means connecting said pair of retaining means to said pivot arm means for causing said retaining means to move from the retracted position to an extended position to engage the cargo at spaced apart locations for retaining the cargo on the platform.
In a preferred form, the apparatus, which is intended for use with a container platform having a top surface defined by rollers, includes a small aim pivotally mounted at the center of the platform and a roller in the frame normally projecting above the platform. When the roller is contacted by a container sliding onto the platform, it causes pivoting of the arm, actuating a pair of linkage assemblies which bias two books upwardly. A first of the hooks (in front of the container in the direction of container movement) pops up into position in the path of travel of the container. The other hook is held down by the container. As the front end of the container engages the first hook, the second hook is free of the container and snaps into position at the rear end of the container to latch the container in position, the hooks preventing vertical and horizontal movement of the container. The hooks are released individually by pedal operated release assemblies. By releasing one end or side of a container, the container can be slid from the platform.